Wheeled locomotive devices have made it increasingly convenient and efficient to transport a payload great distances on a prepared surface or the like, particularly where the wheels are powered by some type of motor. An example of such a wheeled locomotion system is a powered wheelchair for conveniently and rapidly transporting an operator. Such powered wheelchairs have opened up vast realms of opportunity for the disabled by providing means of transportation over streets, sidewalks and hallways.
Although motorized wheelchairs with sophisticated controls are available for the disabled, these devices are restricted to the smooth, prepared surfaces of streets, hallways and the like. Notwithstanding the ability of some skilled operators to maneuver a wheelchair around obstacles such as curbs, it is generally difficult to surmount obstacles with a wheelchair, particularly a powered chair having the increased weight of the motor system. While architectural modifications such as curb cuts, ramps and elevators improve accessibility and are relatively low cost solutions, they are limited. Moreover, wheelchair users often cannot enjoy areas having a non-prepared surface, such as the soft ground of a park or garden, nor can they easily cross patches of mud or surmount potholes, steps and other abnormalities of prepared surfaces.
Although powered wheelchairs are available that have special purpose aids such as stair climbers, these devices are limited in function, are not versatile, and tend to be expensive.
Alternatively, legged vehicles are known that provide for locomotion in environments cluttered with obstacles where wheeled vehicles cannot be used. Statically stable multi-legged robots are known for carrying a payload through such environments. One of ordinary skill recognizes that a multiple legged mobility system is inherently omni-directional and provides superior mobility in conditions which are otherwise generally unpassable by wheeled devices, such as sand. However, such legged devices do not provide the efficiency of traveling great distances on a prepared surface as provided by wheeled systems. Moreover, legged vehicles are not practical for a variety of reasons, including the associated cost and complexity of the system.
Thus, there is a long-felt, yet unfulfilled need for an efficient and practical mobility system for transporting a payload over a prepared surface, as well as over an unprepared surface, and around obstacles such as steps or the like. The present invention provides a mobility system that satisfies this need.